With the recent proliferation of electronics into consumer products, and the consequential requirements for robust electronics residing in a portable enclosure, the adverse effects of contamination and environmental conditions in the enclosure come to the forefront as an issue that must be effectively addressed.
In some attempted solutions a passageway of a controlled size is provided in the enclosure so that internal and external state conditions can seek equilibrium under control, lessening the adverse affects on the enclosure of things like ambient pressure and temperature variation. In other attempted solutions a filter captures contaminants to prevent them from adversely affecting sensitive components inside the enclosure.
Adsorption type filters offer some benefits in that they can advantageously capture and release contaminants such as moisture to maintain a moisture-to-fluid ratio in a range that provides a desired relative humidity. However, sudden changes in temperature are problematic for an adsorption filter system. Sudden heating, such as by starting a motor or placing the enclosure in sunlight, can quickly vaporize too much previously adsorbed moisture, driving the relative humidity in the enclosure too high. Conversely, sudden cooling can quickly condense the previously adsorbed moisture, spilling it onto the electronics components in the enclosure.
Improvements are needed for filtering the enclosure of a device that contains an environment-sensitive component. It is to those improvements that embodiments of the present invention are directed.